Hydraulic hold-down release



Nov. 26, 1968 B. J. ELLIS 3,412,799

HYDRAULIC HOLD- DOWN RELEASE Filed Aug. 5, 1966 2 Sheets-Sheet l 2? y???j z2 3 L l. i5

BY MM/@J7 Nov. 26, 1968 B. L ELLIS HYDRAULIC HOLD-DOWN RELEASE 2Sheets-Sheet 2 Filed Aug.

United States Patent O 3,412,799 HYDRAULIC HOLD-DOWN RELEASE Billy J.Ellis, Houston, Tex., assignor to Schlumberger Technology Corporation,Houston, Tex., a corporation of Texas Filed Aug. 3, 1966, Ser. 570,0551i) Claims. (Cl. 165-120) ABSTRACT OF THE DISCLOSURE A well packerapparatus having support and holddown expanding anchors and including auid passageway having an upper portion in communication with saidhold-down anchors and a 4lower portion in communication with the wellbore below the packer, and valve means for `selectively preventing orpermitting fluid communication between said passageway portions, as wellas tiuid communication between said upper passageway portion and thewell bore above the packer.

This invention relates generally to subsurface well tools and morespecifically to a well packer having hydraulically operable anchoringdevice and fluid pressure equalizing means.

Well packers for performing well bore pressuring operations such assqueeze cementing or hydraulic fracturing `often incorporatehydraulically operated holddown systems which include gripping pistonsadapted to bite into the casing to anchor against upward sliding of thepacker. Cement slurry or fracturing fluid is displaced under pressurethrough a pipe string attached to the packer and into a formation Zone.The pressure difference between the squeeze or fracture pressures andthe annulus hydrostatic pressure is effective as a force urging thegripping pistons against the casing walls. When the pressure operationis completed, the pressures in the pipe string are released and thegripping pistons returned to their retracted positions so that thepacker can be retrieved from the well.

Under certain circumstances, the anomaly of ash setting of cement slurrycan occur in the pipe string and within the packer bore. That is to say,the cement slurry ingredients are improperly mixed at the surface andwill prematurely set up or become hardened when subjected to hightemperatures and pressures normally encountered in a well bore. When thecement slurry hardens, squeeze pressures can be trapped behind thegripping pistons so that they will not retract for release of thepacker. Moreover, in hydraulic fracturin-g operations where propingagents such as sand grains are suspended within a gel, the gel can loseviscosity under high temperatures and pressures to the extent that thesand grains can settle within the tubing string and packer bore so as toform a solid plug therein. This anomoly is called sanding-out and thefracture fluid pressures can be trapped within the hold-down system toprevent its release when sanding-out occurs.

If the hold-down system will not release, the packer must be removedfrom the well by forcing it upwardly by pull on the pipe string at theearths surface until the wickers on the gripping piston are stripped ortorn ol, or by removing the pipe string and attempting to wash over thepacker, or by drilling the packing away. Obviously, any of theseremedial measures involves loss of valuable rig time and/or damage tovaluable equipment.

The leading object of the present invention is to provide a new andimproved hydraulic hold-down system in a well packer wherein uidpressures can be equalized 3,412,799 Patented Nov. 26, 1968 that havebeen trapped in the system to prevent its release.

Another object of the present invention is to provide a new and improvedhydraulic hold-down mechanism which includes an equalizing valve meansoperable upon relative movement between parts to equalize any existingpressure differentials across the gripping pistons which are notequalized in a normal fashion.

Another object of the present invention is to provide a new and improvedwell packer having a fluid bypass and a hold-down mechanism which can bereleased even though lluid pressures are not equalized in a normalmanner when the fluid bypass is open.

Yet another object of the present invention is to provided a new andimproved hydra-ulic hold-down system and pressure equalizing means in awell packer which is elfective to anchor and pack off in a well conduitand which is simple and reliable in operation.

These and other objects are attained in accordance with the presentinvention by providing, in a well packer,

inner and outer tubular members movable longitudinally relative to oneanother. The outer member carries hydraulically operable gripping meansfor anchoring in a well conduit. Passage means and chamber means areprovided between the members through which fluid pressure can act tooperate the hydraulically operable means. Port means in the outer membercommunicate with the well annulus and the valve means can be operated byrelative movement between the members to selectively place the portmeans in communication with the chamber means. Bypass passage means areprovided in the members and bypass valve means can be selectivelyoperated to open and close the bypass passage means.

The novel features of the present invention are set forth withparticularity in the appended claims. The invention, together withfurther objects and advantages thereof, may best be understood byillustration and example of a preferred embodiment illustrated in theaccompanying drawings in which:

FIGURE 1 is a longitudinal partial sectional view of a well packer inaccordance with the present invention with parts in relative positionsfor longitudinal movement within a well bore;

FIGURE 2 is a view similar to FIGURE l with parts in relative positionfor performing a pressure operation in the well bore;

FIGURE 3 is a cross-section taken on line 3 3 of FIGURE 1;

FIGURE 4 is an enlarged fragmentary view of the pressure equalizingmeans in accordance with the present invention when operated to equalizepressures trapped within the hold-down system; and

FIGURE 5 is a developed plan view of the J-slot and lug mechanism usedto control relative movement between parts of the well packer.

Referring to FIGURE l, a well packer 10 in accordance with the presentinvention is shown with parts in running-in positions or forlongitudinal shifting in a well conduit 11. The well packer includes ahydraulically operable anchor assembly A, including a plurality ofgripping pistons 12 for anchoring against upward movement. an expandablepacking assembly B including a plurality of packing rings 13 for packingolf the cross section of the well bore, a lower anchor assembly Cincluding slips 14 and an expander 15 for anchoring against downwardmovement, and a control assembly D including drag blocks 16 whichfrictionally engage the wall of the well conduit 11.

A generally tubular mandrel 20 is telescopically disposed within atubular anchor body 21 for sliding movement between extended andcontracted positions. The

mandrel extends throughout the full-length of the packer and a threadedbox portion 22 at its upper end is adapted for connection with a tubularstring 23 which extends to the earths surface. The lower end of themandrel has a threaded pin portion 24 to which a section of pipe oranother well tool can be connected. Splines 25 and 26 at the upper endsof the anchor body 21 and in the mandrel 20, respectively, may beprovided to co-rotatively and slidably couple the mandrel and anchorbody to one another.

The anchor body 21 has a reduced diameter section 27 around which thepacking assembly B is mounted. The packing assembly includes a pluralityof annular elastomer packing rings 13 made of rubber or rubber-likematerial. The upper end of the packing assembly engages a downwardlyfacing annular shoulder or abutment 28 and the lower end engages anupperly facing annular abutment 29 which forms the upper end of thetypical expander member 15. The expander member 15 has downwardly andinwardly inclined outer surfaces 30 thereon and is retained for limitedmovement relative to the anchor body 21 by an annular flange 31 whichengages in an internal recess 32 in the expander member, the bore of theexpander being sized for sliding movement on the reduced section 27 ofthe anchor body.

Movably mounted on the tubular section 27 of the anchor body 21 is thecontrol assembly D including a cage member 35 which carries theplurality of radially directed drag blocks 16 adapted to frictionallyengage the well conduit wall. A typical I-slot 36 is formed in the lowerend of the cage member 35 and cooperates with a lug 37 extendingoutwardly from the lower end of the tubular section 27 to permit controlof relative movement between the cage member 35 and the anchor body 21.The J -slot 36, shown in developed view in FIGURE 5, has alongitudinally extending segment 38, a horizontal segment 39 and arelatively short vertical segment 40 in which the lug 37 engages whenthe parts are in a running-in" position as shown in FIGURE l.

The cage member 35 has a plurality of circumferentially spaced, radiallydirected recesses 41 in its periphery, each of which receives a dragblock 16. The drag blocks are urged outwardly by springs 42 into africtional engagement with the well conduit wall and function to retardmovement of the cage member 35 in a well known manner. Outward movementof the drag blocks 16 is limited by co-engaging tangs 43, 44 on the cagemember and the drag blocks, respectively.

The cage member 35 also carries a plurality of slip segments 14 whichare movably mounted on the upper end of the cage member by a pluralityof links 45. Each of the slip segments has upwardly and outwardlyinclined inner surfaces 46 slidably engaging the inclined surfaces 30 onthe expander member 15 in a manner whereby relative movement between theslip segments and the expander member will cause outward shifting of theslip segments to engage the well conduit wall. A conventional tongue andgroove connection between each slip segment 14 and the expander member15 may be provided so that relative movement between the slip segmentsand the expander member will effect movement of the slip segments to andfrom the wall of the conduit 11. Wickeis or teeth 47 on the peripheralsurfaces of each slip segment 14 are adapted to bite into the conduitwall and anchor the well packer against downward movement therein.

An upper portion 50 of the anchor body 21 has a plurality of radialcylinders or bores 51 therein, each of which receives a movable grippingpiston 12 having wickers or teeth 52 on its outer face adapted to anchorthe well packer against upward movement when engaged with the wellconduit wall. The gripping pistons 1-2 are pressed inwardly to retractedpositions by springs 53 which bear against retainer bars 54 extendingacross the faces of the pistons and secured on both sides of the pistonsto the anchor body 21 by screws or other suitable fastening means. Asshown in FIGURE 3, each bar 54 iits within a diametrical slot 55 in theface of a respective piston to'prevent the piston from turning in itscylinder and thereby insuring that the teeth 52 are properly oriented inthe direction they will hold. Seal rings 56 encircle each piston 12 anduidly seal between the pistons and the walls of the cylinders 51.

The mandrel 20 is formed with an external annular recess 60 behind thegripping pistons 12 to provide a chamber 61. Fluid pressures developedwithin the chamber 61 in excess of the hydrostatic fluid pressures inthe well annulus will be effective as forces tending to shift thegripping pistons 12 outwardly. When these pressures are equalized, thesprings 53 serve to urge the gripping pistons 12 to their retractedpositions.

A plurality of radial ports 62 in the anchor body 21 are arranged toregister with ports 63 in the mandrel 20 when the Amandrel is extendedto provide a bypass passageway through which well fluids can bypass asthe well packer 10 is shifted up or down in the well conduit: Suitableseal elements 64 are positioned in grooves encircling an -annular valvehead 65 on the mandrel 20 :and function to isolate the ports 62, 63 fromthe chamber 61 behind the gripping pistons 12 whether the mandrel 20 isin its extended or retracted position within the anchor body 21. Theupper of the seal elements 64 also isolates' the ports 62, 63 from oneanother when the mandrel 20 is in its retracted position to seal ofifluid flow through the .i orts. p A lower portion of the mandrel 20 hasan outer surface 66 which is laterally spaced from the inner wallsurface 67 of the tubular section 21 to provide a fluid pressurecommunicating space 68 extending from the lower end of the well packerto a location above the packing assembly B. An annular valve means 70 iscarried by the mandrel 20 intermediate its ends and adjacent the upperend of the communicating space 68. The valve means 70, in theenibodiment shown, can take the form of a tubular sleeve valve having anupwardly extending portion 71 and Van inwardly extending ange 72 at itslower end. The valve is positioned within lan external annular recess 73in the mandrel 20 and will reciprocate with the mandrel as it isl movedbetween its extended and retracted positions within the anchor body 21.The flange 72 serves to laterally space the inner wall of the upwardlyextending portion` 71 from the outer wall of the mandrel recess 73 toprovide a uid passage space 74 therebetween. The passage space '74 is incommunication with the chamber 61 behind the gripping pistons 12 througha plurality of angularly cut slots 75 in the top end of the sleeve valve70.

A plurality of radially directed ports 76 extend through the wall of thelongitudinal Iportion '71 and are :arranged t0 register with a pluralityof radial ports 77 in the anchor body 21 when the parts of the wellpacker are in running-in positions to place the well annulus above thepack-ing assembly B in communication with the passage space 74. Suitableseal elements 78 and 79 may be received in annular grooves in the anchorbody 21 above and below the ports 77 to iluidly seal between the anchorbody and the peripheral surfaces of the sleeve valve 70. Additionally, aseal element 80 can be positioned within opposed i grooves in the lowerend of the sleeve valve and a mandrel shoulder 81 to uidly sealtherebetween.

Thus, it can be seen that when the parts are in running-in positions asshown in FIGURE 1, the chamber 61 behind the gripping pistons 12 is influid communication with the wel] annulus via the slots 75, the passagespace 74, the sleeve valve ports 76 and the anchor body ports 77 so thatuid pressures within the chamber 61 in the Well annulus can beequalized. It can also be seen that when the mandrel 20 is moved to itsretracted position Within the anchor body 21, the sleeve valve 70operates to place the chamber 61 in communication with the communicatingpassage 68 -between the lower portion 65 of the mandrel 20 and the lowersection 27 of the anchor body 21 while closing ot the anchor body ports77. Thus, fluid pressures developed within the mandrel 20 and in thewell conduit 11 below the lower end of the mandrel can be communicatedthrough the passage 68 and the sleeve valve 70 into the chamber 61behind the gripping pistons 12. The longitudinal distance between thelower terminal end of the passage 68 and the gripping pistons 12provides assurance that any tluid movement therethrough as the grippingpistons 12 are operated during a pressuring operation will not besufficient to permit uids such as cement slurry to migrate into thechamber 61 and possibly foul the operation of the gripping pistons.

In the operation, the well packer is assembled as shown on drawings andlowered into the well conduit 11 to a selected setting depth. The lug 37is in the short segment 40 of the J-slot 36 to prevent relative movementbetween the cage member 35 and the anchor body 21, so that the slips 14and the packing rings 13 are retained in retracted positions. Themandrel 20 Vis in its extended position whereby the sleeve valve 70 ispositioned to communicate the chamber 61 with the well annulus so thatfluid pressures are equalized across the gripping pistons 12. The bypassports 62 and 63 are in registry so that ample bypass passage space isprovided for well tluids to bypass around and through the :packingassembly B. Thus, the well packer can be shifted quickly to the desiredsetting depth.

The lower one of the bypass seal elemnets 64 and the seal element J79adjacent the equalizing ports 77 function to completely isolate thegripping pistons 12 from pressure surges within the bore of the mandrel20' and in the passage space 68 between the mandrel and the anchor body21 as the :packer is l-owered into the well. Accordingly, no pressuresare developed within the chamber 61 which can pumlp the gripping pistonsoutwardly as long as the `mandrel 20 is extended. In this manner, theteeth 52 on the gripping pist-ons will not be dulled or damaged byinadvertent engagement with the Well conduit wall.

When setting depth is reached, the well packer is halted. The tubularstring 23 is appropriately manipulated to move the lug 37 into the longsegment 38 of the I-slot 36, the drag blocks 16 frictionally resistingturning movement of the cage member 35. Then the string 12 can be moveddownwardly to move the mandrel 20 and the anchor body 21 relative to thecage member 35 which is held stationary within the well conduit 11 bythe frictional engagement of the drag blocks 16 therewith.

As the mandrel 20 is lowered, the anchor body 21 can move downwardlyrelative to the cage member 35 and the expander member can movedownwardly relative to the slips 14 to expand them into anchoringengagement with the conduit wall. The mandrel can move relative to theanchor body 21 until the box portion 22 engages the top of the anchorbody, this movement positioning the upper one of the bypass sealelements 64 to close the bypass ports 62 and 63 from one another asshown in FIG- URE 2. The sleeve valve 70 is reciprocated downwardly to aposition wherein the latenal ports 76 therein are in communication withthe passage space 68 between the 4anchor body 21 and the lower portionof the mandrel 20. Continued downward movement of the anchor body 21 asthe weight of the tubular string 12 is applied thereto serves tocompress and expand the packing rings 13 into engagement with theconduit wall to seal olf the annulus between the tubular string 23 andthe well conduit 11.

Fluids under pressure can now be displaced downwardly through thetubular string 23, the bore of the mandrel 20 an-d into the conduit 11below the well packer 10. The pressures of the uids are transmittedthrough the passage space 68 and past the sleeve valve 70 into thechamber 61 behind the `gripping pistons 12. A pressure ditferentialacross the pistons sufficient to overcome the force of the springs 53will move the pistons outwardly into gripping engagement with theconduit wall to anchor the well packer against upward movement.

When a pressure operation is completed, the packer can normally bereleased by merely moving the mandrel 20 upwardly to open the bypassports 62, `63. Fluid pressures are equalized within the mandrel bore,the chamber 61 and the well annulus. The springs 53- press the grippingpistons 12 inwardly to retracted positions and the anchor body 21 can bemoved upwardly relative to the cage member 35 for retraction of thelower slips 14 and the packing rings 13.

However, under the circumstances of flash setting during a cementsqueeze or sanding out during a fracturing operation, as previouslydiscussed, the bore of the mandrel 20 can become effectively plugged asshown by the numeral so that even though the bypass can be opened, thesqueeze or fracture pressures are trapped within and below the packer 10by the plugging material. When this occurs, gripping pistons 12 will notdetract from the conduit wall because the pressure differentials betweenthe higher squeeze or fracture pressures and the hydrostatic pressuresin the well annulus continue to be effective as outward forces on thegripping pistons.

The present invention permits the release of the gripping pistons 12 forretrieval of the well packer 10 even under these conditions. Asillustrated in FIGURE 4, the plugged mandrel 20 can be moved upwardlyrelative to the anchor body 21 by an upward pull on the pipe string 23at the earths surface. A small amount of upward movement serves to clearthe ports 76 in the sleeve valve 70 above the lower seal element 79. Thefluid pressures trapped in the chamber 61 behind the `gripping pistons12 can then bleed down and equalize to the lower fluid pressures in thewell annulus through the ports 76 and 77. When the pressures areequalized, the springs 53 can cause retraction of the gripping pistons12 in a normal manner so that the well packer 10 can be retrieved.

A new and improved well packer has been disclosed having means forequ-alizing fluid pressures that may be trapped within a hydraulichold-down system when such pressures are not equalized in a normalfashion by opening the fluid bypass valve. Since certain changes andmodications may be made in the embodiment disclosed, without departingfrom the inventive concepts involved, it is intended that the appendedclaims cover all such changes and modifications.

I claim:

1. In a well apparatus having inner and outer tubular memberstelescopically movable between extending and contracted relativepositions and hydraulically opearable gripping pistons on said outermember for anchoring in a well conduit, the combination therewith ofchamber means communicating with said pistons, passage means betweensaid members, port means in said outer member, and equalizing valvemeans on one of said members selectively operated by telescopingmovement of said members for communicating said passage means andchamber means while closing said port means in one of said positions,an-d for communicating said port means and chamber means while closingsaid passage means in the other of said positions.

2. The apparatus of claim 1 wherein said equalizing valve meanscomprises sleeve means on said inner member, flow means in said sleevemeans arranged to alternatively register with said port means and saidpassage means, and seal means between said sleeve means and said outermember.

3. The apparatus of claim 2 wherein said sleeve means is a tubularmember having a larger bore than the adjacent outer diameter of saidinner member to provide a passage space therebetween, and wherein saidflow means are ports extending laterally through the wall of saidtubular member.

4. The apparatus of claim 1 further including bypass means in saidmembers, and bypass valve means for selectively opening and closing saidbypass means.

5. The apparatus of claim 4 `wherein said equalizing valve meanscomprises sleeve means on said inner member, flow -means in said sleevemeans arranged to alternatively register with said port means and saidpassage means, and seal means between said sleeve means and said outermember.

6. In a well packer for use in a well bore, the combination comprising:inner and outer members telescopcally movable between extended andcontracted relative positions; packing means carried by said members forsealing off a well bore; hydraulically operable gripping members on saidouter member for anchoring against movement in a well conduit; fluidpassage means between said members, said passage means having an upperportion in communication with said gripping members, and a lower portionin communication with the well -bore below said packing means; valvemeans between said members for blocking fluid communication between saidpassage portions in one of said relative positions, and forcommunicating said passage portions with one another in the other ofsaid relative position; and means for communicating said upper portionwith the well bore above said packing means in said one position.

7. In a well apparatus having inner and outer tubular members andhydraulically operable gripping pistons on said outer member foranchoring in a well conduit, the combination comprising passage andchamber means between said members through which iluid pressure can actto operate said hydraulically operable gripping pistons, port means insaid outer member, valve means for selectively placing said port meansin communication with said chamber means, bypass means in said members,bypass valve means for selectively opening and closing said hypassmeans, and seal means between said members for isolating said -chambermeans from the pressures of fluids in said bypass means.

8. A well packer comprising: concentric tubular members relativelymovable between extending and contracted positions; anchor means andpacking means for respectively anchoring said members against downwardmovement in a well conduit and packing off the annulus between saidmem-bers and the surrounding well conduit wall; hydraulically operablegripping means on said members for anchoring against upward movement inthe wellconduit; passage means and chamber means between said membersthrough which iluid pressures can act to operate said hydraulicallyoperable means; port means in the outer of said members; equalizingvalve means actuated by relative movement of said members forselectively placing said port means in communication with said chambermeans; bypass mean-s in said members for bypassing well fluids throughsaid packing means; and bypass valve means for selectively opening andclosing said bypass means.

9. The well packer of claim 8 wherein said equalizing valve meansincludes sleeve means onvthe inner of said members, flow means in saidsleeve means arranged to registed with said port means when said membermeans are contracted, and seal means between said sleeve means and outerof said members above and below said port means.

10. The well packer of claim 8 wherein said bypass valve means includesseal means for isolating said chamber means from fluids passing throughsaid bypass means.

References Cited UNITED STATES PATENTS 2,880,805 4/1959 Nelson et al166-212 X 3,189,095 `6/1965 De Rochemont 166-120 3,233,675 2/1966Tamplen et al 166-134 X 3,277,965 10/1966 Grimmer 166-120 3,283,819ll/l966 Tausch 166-120 3,338,308 8/1967 Elliston et al l66-l 34 X DAVIDH. BROWN, Primary Examiner.

